The United States is seeking to establish a new military alliance with Russia in Syria that would see the two countries join forces in combating jihadist groups, it has been reported.

The proposal, which was reportedly sent to Moscow this week, would mark a striking change in US policy in the region, where the two powers have operated on opposing sides of the civil war.

The deal would see the US and Russia launch a co-ordinated bombing campaign against Jabhat al-Nusra, al-Qa'ida's branch in Syria. In exchange, Russia would be expected to pressure the Assad regime to stop bombing US-aligned rebel groups, an administration official told the 'Washington Post'.